This invention relates to a back-up arrangement associated with the casting belts of a twin-belt continuous casting mold which is particularly adapted for making continuous bars of substantial cross-sectional width. The mold chamber is laterally bounded by side dams formed of side dam blocks articulated to one another and adjoining the casting belts which bound the mold chamber at the top and at the bottom. The casting apparatus has upper and lower end drums which are arranged at the inlet and, respectively, at the outlet of the mold and about which the respective upper and lower casting belts are trained.
The back-up arrangement for the casting belts includes, between the end drums, serially arranged, rotatable central belt supporting components which are in engagement with the casting belt and are in alignment with the mold chamber. The back-up arrangement further has lateral belt supporting assemblies which form stationary belt supporting zones parallel to the length of the mold chamber and which are in contact with the associated casting belt and are in alignment with the side dams.
In the casting of continuous bars which, viewed in cross section, have a relatively large width with respect to the height, and/or in the continuous casting under pressure, risks are high that molten metal penetrates into the zone between the casting belts and the side dam blocks and, as a result, as the mold walls move in the casting direction, fin-like growths may form, necessitating an interruption of the casting process.
U.S. Pat. No. 3,937,274 discloses a casting belt back-up assembly in which, for supporting the casting belts, in the zone of the side dams stationary sliding guides are provided which bridge the intermediate space between the frontal (upstream) and the rear (downstream) end drums. Between the sliding guides, transversely to the length dimension of the casting chamber, support rollers are provided which are spaced at relatively large distances from one another and whose narrow support shoulders engage the adjacent casting belt.
It is a disadvantage of the above-outlined prior art construction that the sliding faces--due to their unchanging position relative to the mold chamber--are heated to very high temperatures during the casting process. In the absence of complex measures for cooling and lubricating the sliding guides, the risk of damages to the twin-belt continuous casting mold--particularly caused by wear of the engaging sliding surfaces--cannot be excluded.